Let’s set out a working definition of what Herd Immunity is at a functional level in the population: Herd Immunity is the presence of adequate immunity within a population against a specific infection that operates to protect those at high risk of serious infection and consequently, reduce morbidity and mortality from that infection.

Now let’s separate out Herd Immunity, comparing what it meant in the pre-vaccine era compared with what it means in the vaccine era, using specific infections as examples.

Measles: Herd Immunity in the pre-vaccine era

When measles first enters a population that has not been exposed to measles before, Herd Immunity is zero and there is, initially, a very high morbidity (illness) and mortality.

This occurs in large part as a consequence of highdose exposure.

High dose exposure occurs because, in the absence of viral immunity, viral replication is unimpeded in the multiple susceptible human reservoirs in which it thrives. High doses of measles virus are transmitted from one person to the next. Added to this, socioeconomic circumstances contribute to high dose exposure. This includes high population density (easy transmission) and poor antiviral defenses (e.g. low vitamins A, D, and C). An example is the ravage of measles in Confederate soldiers amassed in barracks and hospitals in the American Civil War.

Over time, as measles becomes endemic (constantly circulating) in a population with typical 2-yearly epidemics, Herd Immunity increases rapidly. Natural exposure leads to long term immunity. Immunity limits viral transmission and opportunities for viral replication. Concomitantly, developed countries have experienced an improvement in nutritional status and consequently antiviral immunity. Dose of exposure falls and a dramatic reduction in morbidity and mortality is observed.

As a consequence of natural Herd Immunity, in the developed world measles mortality had fallen by 99.6% before measles vaccines were introduced. A fall in morbidity will have paralleled the fall in mortality (mortality is the extreme of morbidity).

Let us look at an example of how natural Herd Immunity operated to provide age-appropriate immunity.

Infants less than one year of age have a limited ability to generate adequate immunity and are susceptible to serious measles infection.

In the pre-vaccine era mothers conferred good passive immunity on their infants by transplacental and breast milk transfer.

This passive immunity protected infants through a period of vulnerability until they were better able to cope with measles through the generation of their own active immunity.

The vaccine era

Measles vaccine has destroyed natural Herd Immunity and replaced it with a temporary and inadequate quasi Herd Immunity that necessitates a dependence on vaccination along with an increased risk of severe adverse outcomes. Here are some examples of how natural Herd Immunity has been destroyed.

The increasing Herd Immunity associated with natural measles and the accompanying decrease in morbidity and mortality, has been interrupted by vaccination. This makes it difficult to predict how vaccinated populations might respond to, say, a new strain of measles virus that has escaped the ‘protection’ conferred by measles vaccine (escape mutant). Because that population is not immune to the escape mutant we risk high morbidity and mortality from measles once again.

Vaccinated mothers do not confer adequate passive immunity upon their infants (< 1 year of age). Infants are unable to generate an adequate immune response to measles vaccine and in the absence of passive maternal immunity, are unprotected during the first year, putting them at risk of serious measles infection.

Unlike natural measles, measles vaccine does not provide lasting immunity and a substantial proportion of measles cases are reported in those who have been vaccinated against measles.

Boosting of immunity using repeated doses of measles vaccine is not sustained and falls off rapidly. The only answer to this diminishing return that is offered by the regulators and manufacturers is to give more and more vaccines. The vaccine is highly profitable in terms of volume of sales, precisely because it is inadequately effective.

Mumps and Herd Immunity

Mumps is acknowledged to be a trivial disease in children; many do not even know they have had mumps the symptoms are so mild. Mumps is not a trivial disease in post-pubertal males where it can cause testicular inflammation and sterility.

Mumps vaccine does not work. Protection is way below the 96% claimed by Merck and mumps epidemics are occurring worldwide in highly vaccinated populations. Merck is accused of fraudulently misrepresenting the efficacy of their mumps vaccine in order to protect their US monopoly on the MMR vaccine. I would suggest that everyone who has suffered mumps and particularly its complications despite mumps vaccination, has a valid legal claim against Merck.

Mumps vaccine failure is associated with inadequate immunity following vaccination (primary failure) and rapidly waning immunity after vaccination (secondary failure). These factors mean that populations are at greater risk as they grow older. Since severe side effects are more common in mature males, mumps vaccine has made mumps a more dangerous disease.

Natural Herd Immunity, that is, lifelong immunity following exposure of children to mumps in the pre-vaccine era, has been destroyed by mumps vaccination.

Chickenpox and Herd Immunity

The chickenpox virus (varicella zoster) causes a mild self-limiting disease in healthy children. The virus frequently establishes latent infection in the cell bodies of sensory nerve roots where it has the potential to episodically reactivate and cause shingles, a very painful and debilitating condition. Shingles can cause blindness. Historically, shingles was an uncommon disease occurring in, for example, people with immune deficiency due to cancer or immunosuppressive drug therapy.

Reactivation of zoster is inhibited by an adequate level of immunity to this virus which, in turn, is maintained by boosting of immunity in parents and grandparents by re-exposure via children with chickenpox. Natural epidemics of chickenpox maintained Herd Immunity by ‘wild-type boosting’ (referring to the natural virus) of adults which prevented shingles in otherwise healthy individuals. This is no longer the case.

Widespread chickenpox vaccination has removed natural Herd Immunity by preventing epidemics, eliminating ‘wild-type’ boosting, and allowing immunity to fall in individuals to the point where shingles is now much more common, occurring in young, apparently healthy people. Vaccination has created a new epidemic to which Merck’s response is, ‘we’ve created a market; now let’s make a vaccine to prevent shingles.’